The present invention relates generally to the correlation of recorded information and more particularly to what is known as framing in video recorders. When information is recorded on a medium, a sync signal is often disposed thereon at a frequency to identify discrete segments of the information. Then by phase locking the sync signals on separate recorded mediums with an external or reference sync signal of the same frequency, the segments of information on the separate recorded mediums are correlated. One application of such information correlation is found in video recording where a discrete segment of information is a field or frame and where recorded information on separate mediums must be correlated or framed for various purposes, such as editing. Many of these purposes, especially editing, require that each separate recorded medium be stopped intermittently and framed again or brought back up to its operational velocity with its recorded sync signal phase locked to the reference sync signal.
Different prior art techniques exist for accomplishing this framing, but most of these techniques are slow because they are limited by the relatively low common frequency of the recorded and reference sync signals, which is usually the same frequency as the frame sync signal or 30 Hz for NTSC systems. Because these prior art techniques are slow, numerous uncorrelated frames or fields are replayed while framing is accomplished. A U.S. patent application Ser. No. 173,629 was filed on July 30, 1980 by R. A. Dischert and J. M. Walter in which a fast framing technique is disclosed and the assignee of that application is also the assignee of the present application. In the Dischert and Walter disclosure, recorded information is framed by accelerating the recorded medium from an intermediate velocity to its operational velocity in distinct intervals between which a constant velocity interval is maintained to phase lock the recorded and reference sync signals when the operational velocity is reached. However, this application fixes the separate durations of acceleration and constant velocity in proportion to the intermediate velocity being utilized.